On a chilly morning in Doncaster, Jessica wishes for windows. The 21-year-old electro-technical apprentice is tasked with fitting a local school's computer lab. This week she's installing sockets and trunking stray wiring but, without glass in the frames or a ceiling overhead, the new extension is cold comfort. Temperature notwithstanding, halfway through the second year of a four-year apprenticeship, Jessica says she's happy in her work. After having a baby at 15, further education proved a financial impossibility. But an apprenticeship, offering a living wage and training on the job, is perfect for her circumstances. "I always said I wanted to keep on learning. I wanted to make something of my life, not just for me, but so my son can see it too."

If unemployment hits 3 million by the end of the year, as expected, 1.25 million of those people will be under 25. While much ink has been spilled over the fate of middle-class graduates in this recession, the reality is that Generation Crunch will comprise many more Neets - those young people "not in education, employment or training", who have already proved a seemingly intractable constituency for the government and are likely to sink further into poverty and dislocation in an economic downturn.

Perhaps with this in mind and perhaps alarmed, as he is said to be, by youth riots in Greece, Gordon Brown last week trumpeted an injection of £140m into the state-funded apprenticeship scheme, creating 35,000 positions. But it isn't only the stated aim of fast-food chain McDonald's to become the UK's biggest apprentice employer that raises the inevitable spectre of McJobs.

Apprenticeships have come a long way since the Youth Training Scheme of the 80s, when teenagers were paid a pittance to learn skills that the market didn't need, without any realistic long-term prospects or clear development. But they still struggle for credibility - in the eyes of young people as well as employers. And it's only if this credibility gap is addressed that Brown's cash injection will amount to something more than a smart way to massage unemployment figures and keep low-attaining kids temporarily off the streets.

First off, the apprenticeship scheme has to win back its target audience. Research by the Barrow Cadbury Trust has found that, in contrast to previous generations, today's young people no longer consider vocational training a worthwhile alternative to further education. This may be a consequence of Labour's dogged pursuit of university places for all, but in practice means that non-academically oriented youngsters are ever more suspicious of getting up in the morning to work at a placement just to ensure their benefits don't get cut.

Second, the question of pay has to be addressed. Apprenticeships do not fall under minimum-wage legislation, though the Low Pay Commission is at least examining this exemption. It's essential that these placements aren't treated by employers as a government-sanctioned method of recruiting cheap labour during a recession, creating a new underclass trapped in dead-end jobs without any prospects.

Consequently, apprenticeships are not a panacea. Those disadvantaged young people the boom passed by have never been socialised into the work world. The majority come from circumstances where worklessness is embedded, and placements need to incorporate some element of mentoring if these individuals are to develop the life skills necessary to sustain a career.

And finally, the new scheme can only succeed if the opportunities it offers are also equal in terms of gender. Despite concerted campaigning by the likes of the YWCA, which supported Jessica's electrical aspirations, numbers of young women entering non-typical apprenticeships are still very low. A combination of poor guidance, discriminatory recruitment and unwelcoming workplace culture means that girls continue to be shunted off into hairdressing or beauty therapy, while the gender pay gap in apprenticeships remains as significant a concern as it is for all working women.

As Jessica, who first trained as a beauty therapist, puts it: "It was only when I learned about diversity and equal opportunities from the YWCA that I found the courage to try something else. I thought something like plumbing was one for the lads, and I felt like I'd be really out of place. But I needed a challenge, and I needed a job that paid me to learn, because when I was at college on benefits I really struggled."

In a report last month, the voluntary sector alliance Transition to Adulthood argued that university expansion was exacerbating the problems faced by a youth underclass, polarising young people between those staying on in education, sheltered from the difficulties of transition into adult life, and a smaller disadvantaged group who are in effect abandoned by the state once they reach 18. As the downturn continues, it suggested that this gulf would only widen, as students delay entering a tough jobs market in which the rest must struggle.

The provision of high-quality apprenticeships is what this group of young people needs. But they must be seen to be high quality, with decent pay and training, offering serious value to young people themselves as well as their potential employers.